1. Field of the Invention
The invention relates to a mounting assembly for fluid actuated components utilizing a pressurized gas or liquid, in particular for components connected together in a pneumatic circuit for producing time delays in marine control systems.
2. Prior Art
Fluid actuated circuits have been used for many years to control propulsion systems, power units, etc., particularly in applications where a manually operated control device is remote from the power unit it is controlling. In marine power plants where a diesel engine powers a vessel through a reversible gearbox, it is usual to provide several control stations remote from the engine and gearbox, for example on the vessel's bridge and in the engine room, and possibly at other stations on the vessel. These several control stations can be connected together and to the engine and gearbox through pneumatic lines. A typical application would be in a single or twin lever control used to control an engine from idle to full throttle, and the gearbox from neutral, to forward and reverse positions. Because the components of a gearbox and propeller shaft can have considerable inertia, it is common to incorporate into the circuit means to delay the receiving of a later command signal at a component until an earlier commenced function has been completed. Such delays are necessary, for example to avoid damage to a gearbox when the manual control is shifted quickly from full ahead to full astern without first allowing the propeller shaft to become stationary before reversing the gearbox. In emergency situations, or with unskilled operators, a fast shifting of a gearbox from full ahead to full astern would normally result in considerable damage to the propulsion system and thus accumulators, relay valves, etc. are commonly provided to ensure that the command signals are received by the various components in a particular sequence, so that an earlier command is completed before a later command is initiated. This type of delay system thus has applications for applying a brake to the propellor shaft when the gearbox receives reversing signals. Other applications include the use of a relay valve where a gearbox is adapted to receive either of two possible signals, but only one signal must be received at a particular time. Still other applications relate to a throttle delay circuit which ensures positive engagement of the clutch before the throttle signal reaches the actuator to accelerate the engine. Other typical circuits include a throttle boost which temporarily raises the engine speed during clutch engagement, and sometimes for a short period after clutch engagement, so as to prevent the engine from stalling due to increased load on the engine.
As can be seen from the above, there are several circuits which can be used singly, or in combination with each other, in a typical marine propulsion assembly. In the past, it has been common to fasten the various components, such as relay valves, shutter valves, accumulators, etc. to a mounting board and to use suitable lengths of flexible pipe or hose interconnecting the various components in the required sequence. As each customer usually has different requirements, the circuits require individual design and manufacturing termed "customizing" and, in many cases this is time consuming and costly. Furthermore, it is not uncommon for a previously installed system to be updated later by adding on additional components for extra features, and this requires either incorporating the additional components into the existing system, which can be difficult, or sometimes a complete rebuilding of the mounting assembly is required, thus incurring additional costs.
To reduce the above problems, it is known to provide a versatile customized mounting plate with a series of grooves in a front face thereof, the grooves intersecting at intersections having enlarged recesses to receive, as required, resilient plugs. A gasket and plate perforated with communication and fastening holes can then be fastened to the front face of the mounting plate to provide passages to openings on the rear face of the plate, and short lengths of "jumper" pipes extend from the openings on the rear face of the plate to interconnect the components. The circuit is customized by assembling the various components as required which communicate with particular grooves and then plugging with the resilient plugs particular intersections through which no pressurized fluid is to flow. When using this structure, high labour costs are incurred for fitting the jumper pipes and difficulties can be encountered due to a limit on the number of possibilities of passage arrangements. Also fluid can leak passed the resilient plugs which produces loss of air or undesirable interactions between components.